From 2 to 3 logical levels in Search

In Toodledo there are currently two logical levels available when you specify a search. At the highest level you select AND or OR ("all" or "any"), and at the second level - in each darker blue block - any additional conditions automatically get the opposite type (OR or AND).

This is a very handy and easy way to set up saved searches - overall much better than RTM, where you have to set up the whole structure manually using some kind of "programming language", but RTM does have one little thing going for it - the capability to nest search criteria to virtually any logical level.

I sometimes miss the ability to simply include or exclude something within one of the blocks of my 2-level searches. Not having a third level causes quite a lot of unnecessary repetition.

I think it would be fully adequate, and fully in line with Toodledo's very user-friendly structure for how searches are set up, to simply extend the number of logical levels from two to three, where the 3rd level would be opposite to the 2nd level (and same as the 1st). In other words, You would set up either an AND-OR-AND hierarchy or an OR-AND-OR hierarchy.

Thanks for the suggestion, but I think that this would add too much complexity to the UI and also to the backend software that has to interpret the rules to match the tasks.

I know that is may get a little too technical for most people, but any boolean expression can be normalized down to 2 levels by using either Conjunctive normal form or Disjunctive normal form. You can look this up on Wikipedia if you want to learn more about boolean algebra. I realize that having a 3rd level might be convenient in some situations, but it is possible to do any search possible with only 2 levels.

About the backend you could be right - I cannot judge that. But as an amateur looking at the fact that RTM can do it without showing any degradation in the respone time, it would not seem to be too hard on the backend. But you could be right (maybe they have had to invest a lot more in servers or something).

As far as the UI is concerned I think you are probably exaggerating. This would probably be just another "fork/split icon" somewhere on the right side - or something else that is very discreet. And you could always make it a Pro feature, and/or require users to actively enable it under Settings, and/or make sure it is adequately described in the help section etc etc. There are ways.

Boolean algebra I do not know, but I fully believe you - and I even know it in my bones that you are right about this being doable with only two levels. It's just that it requires so much repetition of identical statements.